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作 者 ：金发会,李世清,卢红玲,李生秀

期 刊 ：生态学报 2008年 28卷 1期 页码：227~236

关键词：土壤微生物量碳；微生物量氮；氮素矿化势；

Keywords:soil microbial biomass carbon, soil microbial biomass nitrogen, nitrogen mineralization potential,

摘 要 ：以采自于黄土高原差异较大的25个农田石灰性耕层土壤为供试土样，对黄土高原主要类型土壤中微生物量碳（BC）、微生物量氮（BN）和氮素矿化势（N0）的差异性进行了比较研究。结果表明，BC、BN和N0在不同类型土壤间存在显著差异，由关中平原至陕北风沙区，BC、BN和N0总体呈现下降趋势，其中以土垫旱耕人为土最高，简育干润均腐土最低，黄土正常新成土和干润砂质新成土居中：土垫旱耕人为土、简育干润均腐土、黄土正常新成土和干润砂质新成土等各土类平均BC分别为305.2μg•g-1，108.4μg•g-1，161.7μg•g-1和125.4μg•g-1，BN分别为43.8μg•g-1，20.3μg•g-1，26.0μg•g-1和30.6μg•g-1，N0分别为223μg•g-1，75μg•g-1，163μg•g-1和193μg•g-1。土壤氮素矿化速率（k）则以简育干润均腐土最大，干润砂质新成土最低，土垫旱耕人为土和黄土正常新成土居中：土垫旱耕人为土、简育干润均腐土、黄土正常新成土和干润砂质新成土的k分别为0.039 w-1，0.044 w-1，0.031 w-1和0.019w-1。不同类型土壤BC、BN与N0的差异，主要与土壤形成过程、输入土壤的植物同化产物和土壤有机质的差异等有关，从较大尺度进一步证明了在黄土高原，土壤有机质是影响BC、BN的主要因子。研究结果对分析黄土高原土壤生产力形成过程具有一定参考价值。

Abstract:Studying soil microbial biomass carbon (BC), microbial biomass nitrogen (BN) and nitrogen mineralization potential (N0) has significance for evaluating the nitrogen supplying capacity of soil. We measured BC, BN and N0 of four main soil types on the Loess Plateau: Eum Orthic Anthrosols, Hap Ustic Isohumisols, Los Orthic Entisols and Ust Sandic Entisols. Soil samples were collected from the surface of twenty-five locations. The chloroform fumigation extraction method was used to measure microbial carbon and microbial nitrogen in the soils. A long-term alternate leaching aerobic incubation method was used to measure nitrogen mineralization potential of the soils. The results indicated that there were significant differences in the BC, BN, and N0 among the soil types. The values of BC, BN, and N0 declined as the sampling locations moved northward from the Guanzhong plain to the sandy regions in northern Shaanxi Province. The values of BC, BN and N0 were highest in Eum Orthic Anthrosols, intermediate in Los Orthic Entisols and Ust Sandic Entisols, and lowest in Hap Ustic Isohumisols. The values of BC averaged 305.2 μg.g-1 for Eum Orthic Anthrosols, 108.4 μg•g-1 for Hap Ustic Isohumisols, 161.7μg•g-1 for Los Orthic Entisols and 125.4 μg•g-1 for Ust Sandic Entisols. The values of BN were 43.8 μg•g-1 for Eum Orthic Anthrosols, 20.3 μg•g-1 for Hap Ustic Isohumisols, 26.0 μg.g-1 for Los Orthic Entisols, and 306 μg•g-1 for Ust Sandic Entisols. The values of N0 were 223 μg•g-1 for Eum Orthic Anthrosols, 75 μg•g-1 for Hap Ustic Isohumisols, 163 μg.g-1 for Los Orthic Entisols, and 193 μg•g-1 for Ust Sandic Entisols. The mineralization rate constants (k) were highest in Hap Ustic Isohumisols, intermediate in Eum Orthic Anthrosols and Los Orthic Entisols, and lowest in Ust Sandic Entisols. The mineralization rate constants were 0.039 w-1 for Eum Orthic Anthrosols, 0.044 w-1 for Hap Ustic Isohumisols, 0.031 w-1 for Los Orthic Entisols, and 0.019 w-1 for Ust Sandic Entisols. The differences of BC, BN and N0 among most soil types on the Loess Plateau result from the effect of soil forming factors such as climate, topography, parent material, and living organisms. The latter factor includes human activities such as the application of organic fertilizer and the reshaping of the land form through the construction of terraces. This paper provides a reference and guide for analyzing the processes affecting soil fertility on the Loess Plateau.

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